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<head><meta charset="utf-8"><title>implicit lifetime bounds? · general · Zulip Chat Archive</title></head>
<h2>Stream: <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/index.html">general</a></h2>
<h3>Topic: <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/implicit.20lifetime.20bounds.3F.html">implicit lifetime bounds?</a></h3>

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<a name="244988496"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/implicit%20lifetime%20bounds%3F/near/244988496" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Taylor Yu [they/she] <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/implicit.20lifetime.20bounds.3F.html#244988496">(Jul 06 2021 at 02:06)</a>:</h4>
<p>there seem to be a lot of implicit lifetime bounds that aren't documented anywhere obvious. like that <code>&amp;'a T</code> implies <code>T: 'a</code> (apparently a somewhat new implicit bound?) i learned about that one somehow but i can't seem to find it in the Reference</p>



<a name="244988847"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/implicit%20lifetime%20bounds%3F/near/244988847" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Taylor Yu [they/she] <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/implicit.20lifetime.20bounds.3F.html#244988847">(Jul 06 2021 at 02:13)</a>:</h4>
<p>oh. hidden in the Edition Guide <a href="https://doc.rust-lang.org/edition-guide/rust-2018/ownership-and-lifetimes/inference-in-structs.html">https://doc.rust-lang.org/edition-guide/rust-2018/ownership-and-lifetimes/inference-in-structs.html</a></p>



<a name="244990734"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/implicit%20lifetime%20bounds%3F/near/244990734" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Taylor Yu [they/she] <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/implicit.20lifetime.20bounds.3F.html#244990734">(Jul 06 2021 at 02:49)</a>:</h4>
<p>huh, RFC tracking issue <a href="https://github.com/rust-lang/rust/issues/44493">https://github.com/rust-lang/rust/issues/44493</a> was closed three years ago without the documentation update checkbox being checked. this seems like a possible process problem? <a href="https://github.com/rust-lang/reference/issues/289">https://github.com/rust-lang/reference/issues/289</a> is still open</p>



<a name="244990785"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/implicit%20lifetime%20bounds%3F/near/244990785" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Taylor Yu [they/she] <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/implicit.20lifetime.20bounds.3F.html#244990785">(Jul 06 2021 at 02:50)</a>:</h4>
<p>this is not the first time i've seen such a documentation omission. i'm starting to think it's a pattern.</p>



<a name="245060023"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/implicit%20lifetime%20bounds%3F/near/245060023" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Taylor Yu [they/she] <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/implicit.20lifetime.20bounds.3F.html#245060023">(Jul 06 2021 at 15:59)</a>:</h4>
<p>it looks like a lot of the significant undocumented changes about which i'm noticing this pattern were landed in 2018. it's almost like there was a big rush to stabilize a bunch of features (Edition 2018?), and completing the documentation wasn't a high enough priority, nor was documentation considered a requirement for completion of a feature.</p>



<a name="245061854"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/implicit%20lifetime%20bounds%3F/near/245061854" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Taylor Yu [they/she] <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/implicit.20lifetime.20bounds.3F.html#245061854">(Jul 06 2021 at 16:10)</a>:</h4>
<p>i want to be clear: i think Rust is awesome. i think many of the Edition 2018 features, and ongoing feature work, are awesome. i wish it were possible to learn about this awesomeness without needing to be an expert who already knows exactly what RFCs, forum threads, or compiler source code sections to look at to find out how these features are supposed to behave.</p>



<a name="245082034"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/implicit%20lifetime%20bounds%3F/near/245082034" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Taylor Yu [they/she] <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/implicit.20lifetime.20bounds.3F.html#245082034">(Jul 06 2021 at 18:45)</a>:</h4>
<p>github thinks there's 14 issues in the Reference repo tagged "RFC Stabilization Docs" <a href="https://github.com/rust-lang/reference/labels/RFC%20Stabilization%20Docs">https://github.com/rust-lang/reference/labels/RFC%20Stabilization%20Docs</a>, 4 of which are also tagged "S-waiting-on-stabilization", which for some of them seems to be in error. more of half of these issues haven't been touched in over a year.</p>



<a name="245084316"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/implicit%20lifetime%20bounds%3F/near/245084316" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Eh2406 <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/implicit.20lifetime.20bounds.3F.html#245084316">(Jul 06 2021 at 19:03)</a>:</h4>
<p>It is a mess, and not good.</p>



<a name="245084519"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/implicit%20lifetime%20bounds%3F/near/245084519" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Taylor Yu [they/she] <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/implicit.20lifetime.20bounds.3F.html#245084519">(Jul 06 2021 at 19:05)</a>:</h4>
<p>i'm still a relative beginner (to Rust) so my ability to contribute is limited, but i'm trying to fix the places that i've tripped over the hardest</p>



<a name="245084614"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/implicit%20lifetime%20bounds%3F/near/245084614" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Eh2406 <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/implicit.20lifetime.20bounds.3F.html#245084614">(Jul 06 2021 at 19:05)</a>:</h4>
<p>Thank you!</p>



<a name="245084807"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/implicit%20lifetime%20bounds%3F/near/245084807" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Taylor Yu [they/she] <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/implicit.20lifetime.20bounds.3F.html#245084807">(Jul 06 2021 at 19:07)</a>:</h4>
<p>i figure that being a beginner with 20+ years software dev experience gives me a… unique? hopefully helpful? perspective</p>



<a name="245084831"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/implicit%20lifetime%20bounds%3F/near/245084831" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Eh2406 <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/implicit.20lifetime.20bounds.3F.html#245084831">(Jul 06 2021 at 19:07)</a>:</h4>
<p>Edition 2018 was a nightmare for possesses, we hope to never go through that again.</p>



<a name="245084959"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/implicit%20lifetime%20bounds%3F/near/245084959" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Taylor Yu [they/she] <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/implicit.20lifetime.20bounds.3F.html#245084959">(Jul 06 2021 at 19:08)</a>:</h4>
<p><span class="user-mention silent" data-user-id="120179">Eh2406</span> <a href="#narrow/stream/122651-general/topic/implicit.20lifetime.20bounds.3F/near/245084831">said</a>:</p>
<blockquote>
<p>Edition 2018 was a nightmare for possesses, we hope to never go through that again.</p>
</blockquote>
<p>huh, where would i look for more context about that? or is most of it unwritten?</p>



<a name="245085392"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/implicit%20lifetime%20bounds%3F/near/245085392" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Eh2406 <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/implicit.20lifetime.20bounds.3F.html#245085392">(Jul 06 2021 at 19:11)</a>:</h4>
<p>The website was only one part of what went sideways, but it eventually got a retrospective:<br>
<a href="https://blog.rust-lang.org/inside-rust/2020/05/26/website-retrospective.html">https://blog.rust-lang.org/inside-rust/2020/05/26/website-retrospective.html</a></p>



<a name="245085504"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/implicit%20lifetime%20bounds%3F/near/245085504" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Eh2406 <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/implicit.20lifetime.20bounds.3F.html#245085504">(Jul 06 2021 at 19:12)</a>:</h4>
<p>I am not remembering other retrospecives.</p>



<a name="245094202"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/implicit%20lifetime%20bounds%3F/near/245094202" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Taylor Yu [they/she] <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/implicit.20lifetime.20bounds.3F.html#245094202">(Jul 06 2021 at 20:27)</a>:</h4>
<p><span class="user-mention silent" data-user-id="120179">Eh2406</span> <a href="#narrow/stream/122651-general/topic/implicit.20lifetime.20bounds.3F/near/245085392">said</a>:</p>
<blockquote>
<p>The website was only one part of what went sideways, but it eventually got a retrospective:<br>
<a href="https://blog.rust-lang.org/inside-rust/2020/05/26/website-retrospective.html">https://blog.rust-lang.org/inside-rust/2020/05/26/website-retrospective.html</a></p>
</blockquote>
<p>i think i can tentatively infer from that blog that some of the people who would have worked on documenting new features for Edition 2018 burned out and/or left the project</p>



<a name="245095327"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/implicit%20lifetime%20bounds%3F/near/245095327" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Josh Triplett <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/implicit.20lifetime.20bounds.3F.html#245095327">(Jul 06 2021 at 20:37)</a>:</h4>
<p>It's more that it was the first time we'd done an edition, and we didn't know that we should emphasize docs heavily.</p>



<a name="245095342"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/implicit%20lifetime%20bounds%3F/near/245095342" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Josh Triplett <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/implicit.20lifetime.20bounds.3F.html#245095342">(Jul 06 2021 at 20:37)</a>:</h4>
<p>We also underestimated how much time the edition would take, and so things happened last-minute.</p>



<a name="245095367"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/implicit%20lifetime%20bounds%3F/near/245095367" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Josh Triplett <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/implicit.20lifetime.20bounds.3F.html#245095367">(Jul 06 2021 at 20:37)</a>:</h4>
<p>That's one reason the 2021 edition has been much gentler; we've been more willing to say "that isn't going to make the edition".</p>



<a name="245119374"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/implicit%20lifetime%20bounds%3F/near/245119374" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Official AK <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/implicit.20lifetime.20bounds.3F.html#245119374">(Jul 07 2021 at 02:05)</a>:</h4>
<p>Ye</p>



<a name="245119376"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122651-general/topic/implicit%20lifetime%20bounds%3F/near/245119376" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Official AK <a href="https://rust-lang.github.io/zulip_archive/stream/122651-general/topic/implicit.20lifetime.20bounds.3F.html#245119376">(Jul 07 2021 at 02:06)</a>:</h4>
<p>tes</p>



<hr><p>Last updated: Aug 07 2021 at 22:04 UTC</p>
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